The development of a composite collector for the flotation of rutile

A study was carried out to find a replacement for benzyl arsenic acid (BAA) that was used in the rutile flotation circuit of a hard rock rutile mine in China. Several types of oxide collectors were tested, including sodium oleate, sodium laurate, sodium dodecyl sulphate, amino acids, diphosphonic acid and styryl phosphonic acid. It was found that styryl phosphonic acid (SPA) was the most effective, and that an aliphatic alcohol (e.g., octanol) was required to maintain the effectiveness of SPA.However, octanol was insoluble in water. The composite collector that was mixed with SPA and octanol had to be well emulsified before addition to flotation pulp. Poorly emulsified composite collectors destroyed flotation froths. Several surfactants were tested as emulsifiers and one was found to have the least adverse effects on the selectivity of the composite collector. By using the composite collector that contained SPA, octanol and the emulsifier, a rutile rougher concentrate assaying 71.3% TiO₂ was floated at 81.6% recovery from a feed containing 8.78% Ti0₂ in a single stage rougher flotation.     

The flotation separation of scheelite from calcite using a quaternary ammonium salt as collector

The flotability of scheelite and calcite was studied with Dioctyl dimethyl ammonium bromide (BDDA). The experiments were conducted on individual and mixed minerals as a function of pH with a micro-flotation cell. And oleic acid was tested for comparison. The flotation results revealed that the performance of BDDA is better than that of oleic acid and the best separation could be achieved with BDDA over the pH range 8-10. Through preliminary analysis, it is concluded that BDDA reacts with scheelite through electrostatic interaction.     

The behavior of N,N-dipropyl dodecyl amine as a collector in the flotation of kaolinite and diaspore

The flotation behaviors of kaolinite and diaspore were investigated using N,N-dipropyl dodecyl amine (PN). Maximum recoveries of kaolinite and diaspore were about 90% and 50%, respectively. Both recoveries of kaolinite and diaspore increased with the increasing dosage of PN. On the basis of the zeta potential and FT-IR spectra, the ionization of surface hydroxyl and the isomorphic exchange of surface ions account for the charging mechanisms of surfaces of kaolinite and diaspore. The adsorption mechanism of PN on the surface of two minerals was mainly electrostatic. After reacting with PN, the zeta potential of kaolinite and diaspore both increased, and comparing with the original zeta potentials, potential of kaolinite increased much more than that of diaspore, this can explain why recovery of kaolinite is higher than that of diaspore.     

Removal of titanium impurities from feldspar ores by new flotation collectors

The principal impurities in some feldspar ores are titanium and iron, which impart color and in turn degrade the quality of the ore. Mineralogical investigations on the majority of Turkish feldspar ores indicate that rutile and, scarcely, sphene are the major titanium minerals and iron mainly originates from mica minerals. Conventionally, fatty acids, and particularly sodium oleate, are extensively used to float discoloring minerals from feldspar ores with reasonable success. In this study, new collectors, oleoyl sarcosine and hydroxamate, reported for the first time in the literature, have been used to float titanium impurities. It is found that compared to fatty acids these reagents achieve superior results. The mechanism of the action is elaborated on the basis of experimental data.     

Improving copper flotation recovery from a refractory copper porphyry ore by using ethoxycarbonyl thiourea as a collector

In this paper, N-propyl-N-ethoxycarbonyl thiourea (PECTU) collector was investigated to concentrate copper minerals from a refractory copper porphyry ore through bench-scale and industrial flotation tests. The flotation results indicated that PECTU had strongly collecting power for copper sulfide minerals and excellent selectivity against iron sulfide minerals under moderately alkaline conditions. Compared with sodium butyl xanthate (SBX), PECTU increased the grades and recoveries of Cu, Au and Mo in the copper concentrates, and performed the flotation separation of Cu/Fe sulfide minerals at cleaner pH ∼10.5 as well as decreased 2/3 lime consumption. The results of UV-visible measurements further demonstrated that PECTU could be used as a high selective collector for copper minerals. The experimentally obtained results have been explained from the structure-reactivity relationship of collector by density functional calculation.     

Temperature sensitive polymers as efficient and selective flotation collectors

This study investigates both the efficacy and selectivity temperature responsive of poly(N-isopropylacrylamide) PNIPAM as a flotation collector. The results of this study showed that charged poly(N-isopropylacrylamide) polymers selectively increased both the probability particle/bubble attachment as well as the floatability of coarse alumina and quartz particles respectively. These results provide a basis for considering PNIPAM as both an effective and selective collector in a flotation system. Coupled with previous studies that demonstrate the efficacy of PNIPAM as a flocculant in mineral suspensions, these results clearly demonstrate the potential use of PNIPAM as a dual function reagent which acts as both selective flotation collector and flocculant in the flotation of ultrafine particles.     

某低品位稀土矿浮选工艺的改造实践

四川省某轻稀土矿山,原矿伴生萤石、重晶石及等多种有用矿物组分,原有选别原则流程分为稀土重选、稀土浮选、重晶石浮选和萤石浮选四个模块。该工艺方案稀土浮选与重晶石萤石浮选属于两套独立的生产系统,同时,又不可避免地存在着稀土浮选精矿品位与回收率受重晶石萤石浮选的回水相互影响等因素,导致了自投产以来稀土品位与回收率均未能达到设计指标。为此,选矿厂对流程开展了许多长期的考查与改进,对稀土浮选工艺进行其它方案可行性研究。最终确立新的工艺方案将独立的稀土浮选取消,形成了重晶石优先浮选,后稀土与萤石混合浮选,再通过湿式高梯度磁选作业回收浮选精矿中稀土的工艺。新的工艺最终达到了重选加浮选稀土综合回收率到72%以上,浮选精矿ROE品位65%以上的良好指标。     

The effect of the reagent suite on froth stability in laboratory scale batch flotation tests

In batch flotation tests conducted on ores from the Merensky reef, changes in froth stability invariably occur with variations in the reagent suite. The main reagents are collectors (primary and secondary), activators, depressants and frothers. Since the particles entering and leaving the froth in a batch flotation system are continuously changing, the stability of the froth can vary. Under these conditions the simplest measure of froth stability is the measure of water recovery at a fixed froth height. The batch flotation system developed at UCT allows for the separation of gangue which is entrained relative to gangue which is floated. It has been found that the presence of naturally floatable gangue (NFG) leads to froth stabilisation, whereas the presence of hydrophobic sulfide minerals may lead to destabilisation of the froth depending on the hydrophobicity (contact angle) of the sulfide minerals. This can vary with ore type since particle shape and amount of particles present can influence the extent of destabilisation. At low depressant dosages sodium isobutyl xanthate (SIBX) always results in lower froth stability than sodium ethyl xanthate (SEX). The frothing nature of dithiophosphate leads to increased froth stability and the addition of copper sulfate results in destabilised froths. Increasing depressant dosage reduces the stabilising influence of NFG and the depressant type (guar gum or CMC) also affects froth stability. Frother can be used in an attempt to overcome the destabilising effects of high depressant dosage. This work examines the effect of variations in the reagent suite and uses water recovered at a fixed froth height as an indication of froth stability in order to analyse these effects on the recovery of sulfide minerals, floatable gangue and entrained gangue.     

Laboratory flotation separation of INCO bulk matte

Laboratory batch flotation tests were performed on a sample of bulk slow cooled converter matte (Cu:Ni = 1) to optimize the time in each of the separation stages. Numerical simulations were carried out to estimate a continuous circuit material balance for the conditions selected. An experimental simulation of a continuous circuit (locked cycle test) readily came to steady state and there was reasonable agreement between the numerical and experimental results. The use of nitrogen as the flotation gas and the addition of collector to the grinding mill minimized the oxidation of chalcocite, which has previously resulted in increasing circulating loads, and led to a stable circuit with very low weights in the recycle streams.     

Primary biodegradation of sulfide mineral flotation collectors

The primary aerobic biodegradation of several sulfide mineral flotation collectors has been studied, and the kinetic model of biodegradation is also discussed. The results show that sodium diethyldithiocarbamate, ammonium butyl-dithiophosphate, n-butyl xanthate can be readily biodegraded, their primary biodegradation extent can reach 97.1%, 93.7%, 81.8%, respectively in 8 d. However, ethylthionocarbamate is difficult to be biodegraded, with its primary biodegradation efficiency being only 37.3% in 8 d. The rate constants follow the order of: k_{sodiumdiethyldithiocarbamate}>k_{ammoniumbutyl-dithiophosphate}>k_{n-butylxanthate}>k_{ethylthionocarbamate}. Their aerobic biodegradation kinetics can be accurately described by first order reaction kinetics equations.     

微乳型捕收剂的稳定性和浮选性能的试验研究

微乳型捕收剂(Micro-emulsion Collector,MEC)在煤浆中的分散性能优于柴油和乳化柴油,可以有效降低煤泥浮选药剂的用量。MEC的稳定性是影响其工业应用的重要性能指标,国内外学者通常采用静置观察法研究乳化柴油和微乳化柴油的稳定性,难以直观并定量表征微乳液的稳定性和液滴粒径。笔者借助多重散射光稳定性分析仪研究了乳化剂配方和用量、超声波功率及作用时间对MEC稳定性和液滴粒径大小的影响,通过煤泥浮选试验考察了MEC的浮选性能。研究结果表明:制备MEC的最佳工艺条件为,乳化剂用量为柴油质量的5%,含水量为柴油质量的5%,表面活性剂配方为Span80∶Tween40∶Octanol=7∶3∶4,磁力搅拌10 min后用200 W超声波强化处理5 min;乳化剂配方和用量影响MEC的稳定性和液滴粒径大小。乳化剂用量越多,MEC越稳定。乳化剂用量为3%时,液滴易发生聚集,放置一段时间后液滴粒径会超过100 nm。乳化剂用量为7%时,MEC最稳定,液滴初始粒径为69 nm,并随放置时间延长缓慢变大。乳化剂用量为5%时,MEC稳定性好,液滴粒径随放置时间的延长基本不发生变化,保持在37 nm左右;超声波功率低于600 W时,功率越小,MEC越稳定。功率大于600 W时,功率越大,液滴粒径越小,MEC稳定性越好。超声波处理时间为20 min时,MEC的稳定性动力学指数(Turbiscan Stability Index,TSI)值随放置时间延长快速变大,MEC很不稳定;MEC用于煤泥浮选时,能显著提高煤样的接触角,增加煤粒表面疏水性,提高煤粒的可浮性。在相同的捕收剂用量下,浮选精煤产率更高,灰分更低,浮选完善指标更好。     

Rougher flotation of copper sulphide ore using biosolids and humic acids

In the quest of new, less hazardous, and more ambient-friendly froth flotation reagents, the use of biosolids or humic acids as both collector and frother for the concentration of copper sulphide ores was investigated. Rougher flotation tests were conducted in Denver cells on a laboratory scale, and metallurgical indicators such as copper recovery, copper concentrate grade, and concentration and enrichment ratios were compared with those obtained under similar conditions but using conventional collectors and frothers for the industrial flotation of copper sulphide ores. With a dosage of 10% (w/w) biosolids, copper recovery and grade were 26% and 0.81%, respectively. The copper recovery and grade obtained with 1.5% (w/w) salt of humic acids were 29.7% and 3.5%, respectively. A significantly higher copper recovery (65.1%) was obtained with conventional industrial collectors and frothers, but the grade was also low (3.1% Cu). With the same dosage of humic substances, humic acid show that the flotation rate constant was significantly higher (0.2 min⁻¹) than that obtained with the same dosage of biosolids (0.09 min⁻¹). These results indicate that humic acids have more affinity than biosolids for copper-containing mineral species, and also show that biosolids and humic acids could be used as both collector and frother in the sulphide mineral concentration process by froth flotation. Because the distribution of iron in the concentrate obtained with biosolids is highest, these materials seem to have more affinity for pyrite.     

粗细粒级差异化给矿对浮选柱选别性能的影响

粗细粒级矿物具有不同的浮选特性,浮选柱主要应用于精选作业的细粒级矿物分选,对粗颗粒矿物回收率较低,限制了浮选柱的应用。在泡沫层分选理论的基础上,以纯石英矿物(纯度大于99%)为代表矿样,将其分成150~280μm和-15μm粗细粒级两个组分,采用Ф100 mm×2 000 mm浮选柱开展试验考察粗细粒级差异化给矿对选别性能的影响。在一个试验中将粗细粒级矿物混合给入浮选柱泡沫层之下进行常规浮选,在另一个试验中将粗细粒级矿物差异化给入浮选柱泡沫层之上和泡沫层以下分别进行泡沫层分选和常规浮选。试验对比结果表明,粗细粒级差异化给矿提高了浮选柱精矿回收率,对粗颗粒矿物回收效果提升更为显著。     

以辉锑矿为原料放电等离子烧结快速制备黝铜矿Cu12Sb4S13及反应机理

采用辉锑矿为原料成功制备出Cu12Sb4S13块体.研究以Sb2S3矿物为原料时烧结工艺对Cu12Sb4S13合成的影响.在400～440℃温度区间内均可快速合成Cu12Sb4S13块体且二次烧结能够进一步减小中间相CuSbS2和Cu3SbS3.第二相Cu3SbS4和残留相CuS随着烧结时间的延长而降低.二次烧结前进行机械化球磨处理,干磨比湿磨更容易减小残留相.初次烧结块体的断面SEM和EDS能谱分析表明内部存在Cu或Cu2S颗粒团聚现象.适当降低Cu或CuS摩尔量(化学计量比0.1 mol)能促进烧结块表面反应进行.烧结过程中,硫磺蒸汽压的导致烧结块表面成分和内部粉末的成分不同.     

A mixed collector system for phosphate flotation

Flotation has been used in industry for more than a half century as the primary technique for upgrading phosphate. While the flotation of phosphate was inefficient when oleic acid was used alone as a collector, therefore a mixed collector of oleic acid (HOl), linoleic acid (LA) and linolenic acid (LNA) was employed to improve the recovery of phosphate flotation. The batch flotation results showed that the optimal composition of the mixed collector was 54 wt.% HOl, 36 wt.% LA and 10 wt.% LNA. Additionally, the effect of pH on the mixed collector application was studied while considering the surface tension, contact angle and micro-flotation. The results showed that the mixed collector should be used at a pH of 9.5. Above a pH of 9.5, the adsorption of fatty acids dimers on the apatite surface hindered phosphate flotation. The influence of the mixed collector assembly on apatite flotation was also investigated. It was demonstrated that due to its low critical micelle concentration, a sufficiently hydrophobic apatite surface could be generated at a collector concentration of 60 mg/L. In addition, zeta potential experiments suggested that collector adsorption was governed by chemisorption. FTIR and XPS spectra studies further indicated that the chemical reaction involved the carboxyl groups of fatty acids and Ca species at the apatite surface for each fatty acid in the mixed collector.     

Collection zone kinetic model for industrial flotation columns

The collection zone recovery of a flotation column was modeled using a rectangular distribution function for the kinetic rate constant and a tank in series model with different vessel sizes for the residence time distribution. It was demonstrated that an analytical expression can be obtained and that data from large industrial columns fits well, keeping the parsimony principle by using a simple and practical solution. An example for the estimation of the maximum kinetic rate constant, useful for scale-up purposes, is shown using data from industrial flotation columns.     

The influence of the oxidation state of pyrite and arsenopyrite on the flotation of an auriferous sulphide ore

In this paper, the influence of the oxidation state of pyrite and arsenopyrite on the flotation of an auriferous sulphide ore was investigated by different techniques, including electrode, pulp potentials, DRIFT spectroscopy and microflotation tests. In addition, the gold and sulphide recoveries were also investigate, in a laboratory-scale cell, as a function of pulp potential and reagent concentration. It was verified that the presence of oxidation products on the sulphide mineral surface demands a higher collector concentration in order to achieve a satisfactory sulphide recovery. The electrochemical behaviour of pyrite and arsenopyrite indicated that a nitrogen atmosphere can lead to a low pulp potential, which inhibits the formation of oxidation products, enhancing both the free gold and sulphide recoveries. Although copper sulphate activates even oxidised sulphide surfaces, it does not improve free gold recovery.     

Selective flotation separation of spodumene from feldspar using new mixed anionic/cationic collectors

The selectivity in flotation separation of spodumene from other pegmatic aluminosilicates such as feldspar and mica, using a single fatty acid anionic collector, is found to be very difficult. It is attributed to the same surface Al site for interaction with fatty acid. In this study, a collector mixture of sodium oleate (NaOL) and dodecyl trimethyl ammonium chloride (DTAC) demonstrates a high selectivity for the flotation of spodumene from feldspar. The influences of important factors such as molar ratio of the mixed collectors, dosages of calcium chloride, sodium hydroxide and sodium carbonate, and pulp temperature on spodumene and feldspar flotation using the mixed collectors have been investigated through micro-flotation tests. The optimum molar ratio of NaOL and DTAC is found to be 9:1. Sodium hydroxide has to be used as a pH regulator. Without the use of depressants, no selectivity is observed as the flotation of spodumene and feldspar are activated by Ca²⁺. Sodium carbonate must be used as depressant of feldspar. A comparison of the flotation for a lithium pegmatite ore using mixed fatty acid soaps and mixed anionic/cationic collectors (NaOL/DTAC) was carried out by the batch flotation tests. The results indicated that NaOL/DTAC decrease collector consumption by two-thirds. The recovery and grade of Li₂O concentrates increase by 4.93% and 0.31%, respectively.     

云南胶磷矿正浮选捕收剂合成与浮选机理研究

通过三乙醇胺对油酸进行酯化改性,获得油酸酯化改性捕收剂,经红外光谱分析表明,具有明显特征吸收峰。通过浮选机理研究,在试验用量范围内,胶磷矿纯矿物与改性捕收剂作用后接触角可达87.23°(此时上浮回收率达97.87%);油酸改性捕收剂引入亲水基团,CMC提高19.58倍,在水中溶解性增加;同时改性后的捕收剂分子截面积由7.27 ?²增大至9.51 ?²,分子截面积提高了30.81%。药剂作用机理的研究,对与纯矿物来自同一矿山的低品位磷矿石浮选具有较强理论指导意义。     

Influence of important factors on flotation of zinc oxide mineral using cationic, anionic and mixed (cationic/anionic) collectors

In this study, the influences of important factors on smithsonite flotation are investigated. Dosages of sulphidizing agent and collector, desliming prior to flotation and the use of sodium hydroxide instead of sodium carbonate as the pH regulator are essential to the effective recovery of smithsonite in cationic flotation. The appropriate temperature for flotation was found to be 30–40 °C. Sodium hexametaphosphate (SH) and sodium silicate had the greatest selectivity between smithsonite–calcite and smithsonite–quartz, respectively. The results of oleic acid flotation showed that the grade and recovery of zinc were relatively low in comparison with the sulphidization-cationic flotation method. Despite using sodium silicate and SH as depressants in oleic acid flotation, flotation was not selective. Flotation using mixed collectors (Armac C + Potassium Amyl xanthate) showed promising results. The ratio of the mixed collectors and the sequence of addition of mixed collectors were important criteria in attaining true mixed collector flotation.